Description

Ensure the private subnets created in the project's private networks use IP address ranges (CIDRs) that do not overlap with each other, or with networks they will be connected to, such as on-premises networks, VPNs, or other projects on the same vRack.

Rationale

Overlapping address ranges cause routing conflicts, so traffic may go to the wrong network or fail completely. This can break connectivity, make firewall rules unreliable, and prevent future connections between networks. Planning unique ranges avoids outages and keeps network rules predictable.

Impact

  • Routing between networks works correctly

  • Avoids connectivity outages

  • Changing a subnet range may require recreating the network and its resources

Default Value

OVHcloud does not prevent you from creating subnets with overlapping ranges in different networks.

Pre-Requisites

  • Permission to manage the Public Cloud project

  • A network address plan

Test Plan

  1. Log in to the OVHcloud Control Panel at https://www.ovh.com/manager/.

  2. In the left-hand menu, select Public Cloud and choose your project.

  3. In the left-hand menu, under Network, select Private Network and review the subnet ranges of each private network and region.

  4. Compare them with each other and with connected networks.

  5. If any ranges overlap, follow the implementation steps.

Implementation Steps

  1. Log in to the OVHcloud Control Panel at https://www.ovh.com/manager/.

  2. In the left-hand menu, select Public Cloud and choose your project.

  3. Create a new private network with a non-overlapping subnet range.

  4. Move the affected resources to the new network.

  5. Delete the old network once it is empty.

Backout Plan

  1. Log in to the OVHcloud Control Panel at https://www.ovh.com/manager/.

  2. In the left-hand menu, select Public Cloud and choose your project.

  3. Move the resources back to the original network and delete the new one.

Reference